This invention relates to a medical unit or device aimed at improving the conditions of the setting and holding of an implant in an anatomical duct, particularly in the case of a vascular implant or endoprosthesis for aneurysm that must be set at least partly by percutaneous endoluminal access.
Various types of implants and various techniques for setting them are already known.
For instance, the patents U.S. Pat. No. 5,527,355 or U.S. Pat. No. 5,707,378 show a device and a method for treating aneurysms through the fitting of a strap around the vessel outer surface, where spring-like means are used to hold the implant against the vessel (stents).
Is thus known a medical unit for the treatment of an affection of an anatomical duct, comprising:
an implant that can be introduced in the duct to be treated, the implant having a general axis and presenting, substantially along said axis, two free ends, respectively proximal and distal, PA1 at least one lining, to at least partly line the outer duct wall, essentially opposite the proximal end of the implant, PA1 and means for fastening the lining to the implant, through the duct wall, so as to hold internally the implant against the duct wall.
According to these patents, as many as two lining straps have been provided on both proximal and distal ends of the implant, which is itself designed so as to be introduced in a radially restrained state. Thereafter, it expands radially to treat the aneurysm.
Nonetheless, some problems remain, related to the conditions under which the strap is set around the given duct and the implant is fastened to this duct wall, as well as to the possible fluid tight conditions required vis-a-vis the circulating fluid.
It will be noted that, in the aforementioned patents, the method used to fasten each strap around the duct can cause a problem, especially if the aorta is concerned, since it can be particularly difficult to try to completely surround it.
Moreover, the physician may find it difficult to succeed in positioning the lining strap exactly across from the corresponding end of the implant, which nonetheless must be done to insure an adequate fastening between them. This fastening is indeed achieved by the hooks connected to one of the implant stents.
The way in which this invention solves the problem consists in particular in providing a medical unit that also includes means of setting the fastening elements, which are distinct from the implant, so as to preferably install these fastening means from the outside of the duct, toward the implant.
Hence the implant fastening hooks are not used to bind together the lining, the duct and the implant. Moreover, according to the invention, the implant could be devoid of any fastening hook to anchor it in the duct.
Approaching the duct from the outside appears to be technically the least dangerous so far for the patient, all the more so if, as otherwise suggested, the fastening between lining strap(s) and implant is performed, through the duct, by means of surgical staples set in place by a surgical stapler designed to introduce and curve the free ends of each staple from only one side of the given duct. An endoscopic (or laparoscopic) approach is proposed.
It is to be noted that these "staplers," including the endoscopic staplers (such as the one from ETHICON.COPYRGT. in U.S. Pat. No. 5,470,010 or U.S. Pat. No. 5,333,772), have not been designed so far to staple through a duct where a fluid circulates (such as a blood vessel), because of possible leaks due to the perforation caused by the staple. It is thus an application that is uncommon to date and goes against the current instructions for the use of such an equipment.
It should also be noted that the choice of both the stapler and the staple is of great significance. A cutaneous stapler (such as a stapler like ROYAL.RTM. from the firm AUTOSUTURE) seems unsuitable in that the staple is initially lying flat, until the stapler closes it progressively to a shape of a U with its free ends curved inwardly by driving the staple forward and then closing in its free ends. What is a priori an effective way to draw together two lips of a cut does not seem appropriate to a fastening through an internal duct containing body fluids, a fragile vessel especially.